Scanning Systems

ABSTRACT

The present application is directed toward cargo scanning systems having scanners, each arranged to scan a respective object and generate a set of scan data, processors arranged to process each set of scan data to determine whether it meets a predetermined threat condition, workstations, and data management system arranged to direct data that meets the threat condition to one of the workstations for analysis.

CROSS REFERENCE

The present application is a national stage application ofPCT/GB2009/000575, filed on Feb. 27, 2009, which further relies on GreatBritain Patent Application Number 0803644.4, filed on Feb. 28, 2008, forpriority. The applications are incorporated herein by reference in theirentirety.

FIELD OF THE INVENTION

The present invention relates to scanning systems. It has particularapplication in scanning systems for cargo.

BACKGROUND

There is a requirement to be able to screen cargo items for the presenceof illicit materials and devices for the protection of the public.

Currently, such inspection may be undertaken using X-ray based screeningapparatus. In these systems, an X-ray image of the object underinspection is taken and an operator reviews this image to resolve, intheir experience, whether the cargo is clear for onwards travel orwhether the cargo requires a further level of inspection. Howevergreater volumes of cargo traffic and greater desire and need forsecurity scanning have lead to an increasing need to increase thethroughput of scanning systems.

SUMMARY OF THE INVENTION

The present invention provides a cargo scanning system comprising aplurality of scanners each arranged to scan a respective object andgenerate a set of scan data, processing means arranged to process eachset of scan data to determine whether it meets a predetermined threatcondition, and data management means arranged to direct data that meetsthe threat condition to a workstation, or one of a plurality ofworkstations, for analysis.

The present application is directed toward cargo scanning systems havingscanners, each arranged to scan a respective object and generate a setof scan data, processors arranged to process each set of scan data todetermine whether it meets a predetermined threat condition,workstations, and data management system arranged to direct data thatmeets the threat condition to one of the workstations for analysis.

The data management means may comprise a job dispatcher. The jobdispatcher may be arranged to coordinate the tasks which are directed toeach of the workstations. The data management means may further comprisea threat detection processor, which may be arranged to process imagedata to allocate the data to a threat category automatically, forexample using one or more image processing algorithms. The datamanagement means may also comprise a threat injector, which may bearranged to input test image data defining an image of a threat item.These different functions of the data management system can be providedas separate processors, or can be provided as different functions of asingle processor.

The system may further comprise a cargo movement control means arrangedto control movement of the objects through the scanners. Where thesystem is arranged to scan cargo carried on road-going vehicles themovement control means may include traffic lights and other signs andindicators for the driver of the vehicle. Where the system is arrangedto scan rail cargo, the movement control means may include points on therailway. Where the system is arranged to scan cargo on a conveyor, themovement control means can include the conveyor.

The system may further comprise a holding bay and the movement controlmeans may be arranged to hold one of the objects in the holding bay inresponse to the object meeting the threat condition. The movementcontrol means may be arranged to cause the object to bypass the holdingbay if it does not meet the threat condition.

According to some embodiments of the invention, a multi-level inspectionprocess is provided which seeks to automate the scanning process toallow higher throughput and lower screening cost per cargo item.

The present invention further provides a method of scanning cargocomprising providing a plurality of scanners, scanning a respectiveobject with each of the scanners to generate a respective set of scandata, processing each set of scan data to determine whether it meets apredetermined threat condition, and directing data that meets the threatcondition to a workstation for analysis.

Preferred embodiments of the present invention will now be described byway of example only with reference to the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic diagram of a scanning system according to anembodiment of the invention;

FIG. 2 is a schematic view of part of the scanning system of FIG. 1;

FIG. 3 is a schematic plan view of a scanning system according to afurther embodiment of the invention;

FIG. 4 is a schematic diagram of a threat detection system forming partof a scanning system according to a further embodiment of the invention;and;

FIG. 5 is a schematic diagram of a cargo security system according to afurther embodiment of the invention.

DETAILED DESCRIPTION OF THE INVENTION

Referring to FIG. 1, a scanning system according to one embodiment ofthe invention comprises a number of scanners 10, which can be forexample static, moving gantry or mobile scanners, each of which isarranged to scan a cargo container to generate image data. In this casethe scanners 10 are arranged over a roadway 11 so that they can scanroad-going cargo trucks. A storage array 12, threat detection processor14 and job dispatcher 16, which generally includes a computer with aprocessor, are all connected to the scanners 10 and to each other by adata switch 18 or other suitable data transmission system. The dataswitch is also connected to a network of workstations 20. Each of theworkstations 20 includes a display 22 arranged to display the image datain the form of an image for viewing by an operator, and a user input 24,in this case in the form of a mouse, which enables the operator toallocate one of a number of threat categories to each image.

The scanners 10 are able to operate independently and at highthroughput. A typical scanner comprises an X-ray generator 30, a set ofX-ray detector arrays 32, 34 each comprising a number of individualdetectors 36 each arranged to generate an output signal. The scanner maybe a drive-through scanner, or it may include means, such as a movablegantry, to scan the cargo item through an X-ray beam which fires fromthe X-ray generator 30 through the cargo item and onto the set of X-raydetectors 36. A two-dimensional image data set is formed by the scannerfrom the detector output signals. That data set contains informationabout the cargo item under inspection. In some embodiments more than oneX-ray beam is used. In this case the beams may be used to generatetwo-dimensional image data sets, or three dimensional image data sets.In either case the image data from a series of scans is typically in aform that can be used to build up a three-dimensional image of the cargoitem. The scanners 10 pass the image information through the data switch18 which is able to route the information directly from the scanners 10to the other nodes 12, 14, 16, 20. Typically, a scan will generate datain the form of Ethernet packets and the data switch 18 is thereforesimply an Ethernet switch.

In the embodiment described here, data from the scanners 10 is passeddirectly to the central storage array 12 and the job dispatcher node 16which is therefore arranged to receive from the generating scanner 10the new cargo image data.

The job dispatcher 16 is then arranged, on receipt of any new image dataset, to allocate time on the threat detection processor 14 for automatedanalysis of the new image data. Advantageously, the image data producedby the scanner 10 will have multi-energy attributes such that a detailedmaterials discrimination algorithm can be executed first by the threatdetection processor 14, followed by an automated detection algorithm.Once the threat detection processor has analysed the image data producedby the scanner 10, it is arranged to notify the job dispatcher 16 of itsconclusions.

If a threat item (e.g. a material or device) has been detected by thethreat detection processor 14, the job dispatcher 16 is arranged toallocate an operator to review the image data produced by the scanner toresolve the severity of the threat item(s) that were detected by thethreat detection processor 14, and to transmit the image data to one ofthe workstations 20, or simply make the data available for retrieval andanalysis by the operator. The operator will utilise one of the networkedoperator workstations 20 that has the capability to manipulate the imagedata for optimal display.

Once the operator has made their decision, and input it as an operatordecision input to the workstation using the input device 24, the result(either that the cargo is in fact clear for onwards travel or that itdoes indeed contain threat materials or devices) is forwarded to the jobdispatcher 16 by the operator workstation. This can be done by sendingthe image data back with the decision attached to it in the form of athreat categorization, or by sending the decision, again for example asa threat categorization, with an identifier which uniquely identifiesthe image data set. The job dispatcher 16 is then arranged to notify thescanner 10 of the result.

In the event that a cargo item is flagged or categorized by the operatorat the workstation 20 as containing a threat material or device, thefacility manager is also notified, and a traffic management systemcontrolled as described in more detail below to direct the cargo itemsappropriately, such that the threat cargo item can be quarantined untilsuch time as an operative is available for manual search of the cargoitem.

Typically, the threat detection processor 14 can be optimised to delivera low false alarm rate to minimise the congestion and process delaysthat are caused when a threat cargo item is detected. The corollary ofthis is that the true detection rate will also be low. In thissituation, very few operators are required in order to inspect imagedata from large numbers of scanning devices. This ensures a lowscreening cost per cargo item.

In this low false alarm rate scenario, it is reasonable to send afraction of all the scanned images to the network of operators usingrandom scheduling of cargo items which were cleared by the threatdetection processor 14. This ensures that good inspection coverage ofall the cargo items that are passing through the facility is achieved.

In a further mode of operation of the system, the balance between falsealarm rate and detection probability is adjusted such that a higherdetection rate is achieved but with a consequent increase in false alarmrate. In this scenario, more operators will be required in order toconfirm or reject the cargo items following automated threat detectionprocessing. At this higher false alarm rate level, it is unlikely thatadditional random inspection of automatically cleared containers will berequired. The use of more operators pushes up the cost of screeningcontainers but this comes at the benefit of an enhanced detectionprobability.

The threat detection processor 14 can be set to any particularsensitivity to suit the environment in which the system is to be used.However in this embodiment the sensitivity of the threat detectionprocessor 14 is adjustable so that the operation of the system can beadjusted to suit the prevailing conditions. This means that where thethreat detection processor is arranged to allocate each item to one of anumber of threat categories, corresponding to different levels ofthreat, the category to which any particular images will be allocatedcan be adjusted so as to adjust the proportion of items that will beallocated to each of the categories. The threat detection processor canbe arranged to adjust this allocation on the basis of one or moreinputs, for example inputs indicative of an overall threat level, thevolume of traffic which needs to be scanned, or the number of operatorsavailable to review the images. In a modification to this arrangement,the threat detection processor 14 can be arranged to allocate the itemsin the same way at all times, and the job dispatcher 16 can be madeadjustable so that it allocates jobs to the workstations, and controlsthe flow of traffic in a way which is variable and adjustable inresponse to the same variables.

In a further embodiment of this invention, a further network node isadded in the form of a threat injector 40. The threat injector node 40comprises a computer 42 having a processor 44 and memory 46, with alibrary, stored in the memory 46, of images of threat items that havebeen collected under controlled conditions using scanners identical tothose 10 in use in the installation. Using a scheduling algorithm thatis controlled by the job dispatcher 16, image data that has been clearedby the threat detection processor 14 is passed to the threat injector40. The threat injector 40 superimposes a threat object image from itslibrary of stored images into the true cargo image in order to create ahybrid image that now contains a known threat in an otherwise clearimage.

This hybrid image is then dispatched by the job dispatcher 16 to one ofthe workstations 20 for an operator review. The operator will beexpected to find and mark the threat object. When the operator threatcategorization decision is input at the workstation 20 and returned tothe job dispatcher 16, the job dispatcher will send a notification tothe workstation 20 to notify the operator that a known threat had beeninserted into the image and will confirm whether the operator locatedthe threat correctly. This information is then stored in a database ofrecords, as part of one of the records which is relevant to theparticular operator, in order to build up a picture of the individualoperator's performance standard.

In a practical realisation of this invention, each workstation 20 can bearranged to display to an operator approximately 10% hybrid threatimages, and 90% pure scanned images, in order to keep them occupied andwell trained. The nature and complexity of the threat images that areinjected are arranged to be variable and dependent on the identity ofthe operator, so that the testing can be balanced against theperformance ability of the observer. This allows targeted trainingprogrammes to be established by the facility managers to ensure optimalhuman operation of the screening system.

In a modification to this system, instead of a hybrid image beinggenerated as described above, a test image representing a threat objectis simply selected from a library of test images and sent to one of thework stations 20, and the response of the operator monitored to seewhether their categorization of the image is correct.

The job dispatcher 16 can be arranged to allocate jobs to individualworkstations or workstation operators on the basis simply of the currentworkload of each operator, which the job dispatcher can determine fromthe tasks it has already allocated, and results it is waiting for fromeach operator, and the threat category to which the threat detectionprocessor has allocated the item. However where the system has a recordor profile associated with each operator, the allocation of tasks tooperators can also be made on the basis of the profile. For example insome case the threat detection processor may allocate items to differentcategories not just on the basis of a level of threat that it associateswith the item, but also on the basis of the type of threat, for examplethe type of threat object that has been detected or the category ofthreat material that has been detected. Where the operator profileincludes types of threat that each operator is able to analyse, or adegree of proficiency of each operator at analysing each type of threat,the job dispatcher can allocate each task to an operator at least on thebasis of this information to match each task to an operator suitable toperform it.

Each operator workstation 20 has the facility to annotate the displayedimage, in response to inputs from the user input 24, in order to mark upan image to indicate the presence and type of threat objects andmaterials that have been detected in the cargo item.

In a further modification to this embodiment of this invention, tofacilitate the smooth operation of each scanning device 10, the jobdispatcher 16 is able to cause the scanning system to route the passageof cargo items at its exit depending on the results of the automateddetection processor and of any subsequent human inspection of the imagedata. For example, as shown in FIG. 2, each of the scanners 10 can havea holding bay 50 which a vehicle can enter after passing through thescanner, with a traffic control system, such as traffic lights 52,arranged to direct vehicles that have passed through the scanner 10 intothe holding bay, or past the holding bay 50. If the automated threatdetection processor 14 detected the presence of a threat item ormaterial, of the traffic lights 52 adjacent to the scanner 10 will becontrolled by the job dispatcher 16 to direct the load to the holdingbay 50 until such time as the operator has input their response. Whenthe operator response has been received by the job dispatcher 14 it isarranged to control further traffic controls, such as a further set oftraffic lights 54, to indicate that the cargo is free to leave thescanning site, or that it needs to move on to another area for examplefor manual searching.

To maximise throughput of the installation, the automated threatdetection processor 14 is arranged to generate a decision relating to acargo item in a time period which is short compared to the overallscanning time for the cargo item. The job dispatcher 16 is arranged tobe capable of allowing a scanner 10 to continue scanning new cargo itemseven if a cargo item is located in the associated holding bay 50awaiting an operator decision.

The embodiments of FIGS. 1 and 2 are arranged to scan and control cargocarried on road vehicles, and the traffic management systems thereforerely on traffic lights and other suitable indicators or signs to directthe driver of the vehicle where to drive. However in another embodimentthe system is arranged to scan cargo transported by rail. In this casethe traffic management systems comprise traffic lights and also pointson the rail tracks, for example at the exits 62 from the scanners inFIG. 3, that can be switched to determine the route which the cargotakes.

The job dispatcher 16 is also arranged to control queuing of multiplesuspect cargo items in the holding bay in order to maximise throughputof the screening installation.

Referring to FIG. 3, in a further embodiment, a security installation issimilar to that of FIG. 2 but comprises a number of scanners 60, eachwith an associated traffic control system 61, and arranged to scan cargoitems in parallel. The exits 62 from all of the scanners 60 lead to ashared quarantine area 64 that serves all of the scanning systems 60.The traffic control systems 61 which comprise traffic lights orequivalent traffic management systems, are arranged to direct trafficeither straight through scanners 60 to the exit of the scanninginstallation or, in the event of a threat being detected, to direct theload to the quarantine area 64 where further traffic management systems66 are provided and arranged to route cargo loads to the exit of theinstallation following manual search as required.

Referring to FIG. 4, in further embodiments of the invention, which canbe otherwise similar to those of FIGS. 1 to 3, the job dispatcher 16 ais similar to that of FIG. 1, but is also arranged to receive, use andmanage one or more different forms of information in addition to X-rayimage data. This could typically include video images of the cargo load,which the job dispatcher 16 a is arranged to receive from one or morevideo cameras 70. It can also include optical character recognition datarelated to container numbering, which can either be obtained by an imageprocessor 72 arranged to process images from the video cameras, or aseparate processor 74 arranged to receive and process images from animaging device 76 specifically arranged to image a part of the containerthat carries the numbering. The information can also include scannedimages of manifest information that may be provided with the cargo item.It may include data from secondary sensors such as weighbridge data froma weighbridge 78 indicative of the weight of the container, data fromchemical detectors or ‘sniffers’ 80 indicative of the presence of one ormore chemical compounds in the container, passive gamma ray data from agamma ray detector 82 or neutron sensing data from a neutron sensor 84.The secondary sensors are shown here is present at the scanner site andpart of the installation, but any of them can equally be at a separatelocation, and arranged to store the data they provide on a data carrierso that it can be input to the job dispatcher, or to transmit the datato the job dispatcher with some form of identification of the containerit relates to. Where this ancillary data is available, the jobdispatcher 16 a is typically arranged to pass the data to the automatedthreat detection processor which is arranged to use it as an input tothe threat detection algorithm that it uses in order to assist it inmaking the best possible threat categorization decision.

Referring to FIG. 5, in a further embodiment of the invention a cargosecurity system is similar to that of FIGS. 3 and 4, but the system isarranged to scan cargo carried by rail on a rail train 81. The parts ofthe system are distributed over larger distances so as to enable anefficient flow of cargo traffic. The system is arranged to scan andcategorize cargo arriving at a port 80 on a vessel 82. The systemincludes a number of scanners, and all of the sources of secondary datadescribed above with reference to FIG. 4, but these are distributed at anumber of locations 84 along the rail route between the port 80 and afinal quarantine or checking area. In particular the scanners 60 are atone location 84 a close to the port 80 where they can be used to scanthe cargo shortly after it has been loaded onto the rail vehicle 81, andthe final checking area is provided at another location 84 b furtheraway from the port which may be at a destination of the cargo where itis removed from the rail vehicle 81 carrying it, and any individualcargo items or containers which are identified as a possible threat canbe checked without delaying the progress of containers which are notidentified as a threat. A traffic management system similar to that ofFIG. 3 including rail points and traffic lights is used to control theroute of each item of cargo, into or past the checking area 86,dependent on the analysis of the scan data and other secondary data bythe threat detection processor. This arrangement means that the cargoitems do not need to be delayed close to the port 80, and can be movingaway from the port, and towards their final destination, while thethreat detection analysis is being performed.

We claim:
 1. A cargo scanning system comprising: a plurality of scannerseach arranged to scan a respective object and generate a set of scandata, processing means arranged to process each set of scan data todetermine whether it meets a predetermined threat condition, a pluralityof workstations, and data management means arranged to direct data thatmeets the threat condition to one of the workstations for analysis.
 2. Asystem according to claim 1, further comprising storage means arrangedto store the scan data, wherein the data management means is arranged tocontrol the storage means to control the supply of data to theprocessing means.
 3. A system according to claim 1 wherein the datamanagement means is arranged to control the supply of scan data to theworkstations.
 4. A system according to claim 1 wherein each workstationincludes a user input to enable a user to provide an input allocatingthe scan data to one of a plurality of threat categories.
 5. A systemaccording to claim 1 further comprising a cargo movement control meansarranged to control movement of the objects through the scanners.
 6. Asystem according to claim 5 further comprising a holding bay wherein themovement control means is arranged to hold one of the objects in theholding bay in response to the object meeting the threat condition.
 7. Asystem according to claim 6 wherein the movement control means isarranged to cause the object to bypass the holding bay if it does notmeet the threat condition.
 8. A system according to claim 5 whendependent on claim 4 further comprising a checking area wherein themovement control means is arranged to control movement of one of theobjects to the checking area if a user input allocates it to apredetermined threat category.
 9. A system according to claim 8 whereinthe movement control means is arranged to control movement of an objectso as to bypass the checking area if the user input does not allocate itto the predetermined threat category.
 10. A system according to claim 4wherein the data management means is arranged to generate a control dataset including a representation of a threat object and to monitor thethreat category to which a user allocates the scan data.
 11. A systemaccording to claim 10 wherein the data management means is arranged togenerate the control data set by modifying one of the scan data sets soas to include a representation of a threat object.
 12. A systemaccording to claim 9 wherein the data management means is arranged tomonitor the threat categories allocated by a plurality of workstationusers to modified data sets, and to generate a profile of the accuracyof each user's allocation.
 13. A system according to claim 1 wherein theprocessing means is arranged to receive at least one set of secondarydata associated with the object and to process the secondary data aswell as the image data to determine whether the threat condition is met.14. A system according to claim 13 wherein the secondary data comprisesat least one of the following: weighbridge data, chemical detector data,gamma ray detector data and neutron sensor data.
 15. A method ofscanning cargo comprising: providing a plurality of scanners, scanning arespective object with each of the scanners to generate a respective setof scan data, processing each set of scan data to determine whether itmeets a predetermined threat condition, and directing data that meetsthe threat condition to one of a plurality of workstations for analysis.